This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A129860 #23 Dec 18 2020 19:40:40 %S A129860 1,1,1,1,2,2,4,6,11,18,37,66,135,265,552,1132,2410,5098,11020,23846, %T A129860 52233,114796,254371,565734,1265579,2841632,6408674,14502229,32935002, %U A129860 75021750,171404424,392658842,901842517,2076217086,4790669518,11077270335 %N A129860 Number of unrooted bifurcating tree shapes with n leaves. %C A129860 Alternatively, the number of unrooted, unlabeled binary tree topologies with n leaves. - _Steven Kelk_, Jul 22 2016 %C A129860 This sequence is identical to A000672 (3-valent trees, boron trees, or binary trees) except the offset is different. A000672 is the main entry for this sequence and has much more information (including a b-file with many more terms). Thanks to _Steven Kelk_ for noticing the errors in the present sequence (which have now been corrected), and for discovering the connection with A000672. - _N. J. A. Sloane_, Jul 22 2016 %D A129860 Joseph Felsenstein, Inferring Phylogenies. Sinauer Associates, Inc., 2004, page 33. Note that at least the first two editions give an incorrect version of this sequence. %H A129860 Jean-François Fortin, Wen-Jie Ma, Witold Skiba, <a href="https://arxiv.org/abs/2006.13964">Seven-Point Conformal Blocks in the Extended Snowflake Channel and Beyond</a>, arXiv:2006.13964 [hep-th], 2020. %H A129860 Jean-François Fortin, Wen-Jie Ma, Witold Skiba, <a href="https://arxiv.org/abs/2009.07674">All Global One- and Two-Dimensional Higher-Point Conformal Blocks</a>, arXiv:2009.07674 [hep-th], 2020. %Y A129860 Essentially the same sequence as A000672. %K A129860 nonn %O A129860 2,5 %A A129860 _Barry Cipra_, May 23 2007 %E A129860 Entry revised by _N. J. A. Sloane_, Jul 22 2016 at the suggestion of _Steven Kelk_